docs: def start(bt_device=''):
          '''
          Attributes:
             device (string): BLE device (default hci0)
          '''
          # import ptyprocess here so as long as all implementations are in the same file, all will work
          import ptyprocess
  
          if not bt_device:
              bt_device = 'hci0'
  
          log.info('Start receiving broadcasts (device %s)', bt_device)
          DEVNULL = subprocess.DEVNULL if sys.version_info >= (3, 3) else open(os.devnull, 'wb')
  
          subprocess.call('sudo hciconfig %s reset' % bt_device, shell=True, stdout=DEVNULL)
          hcitool = subprocess.Popen(['sudo', '-n', 'hcitool', 'lescan', '--duplicates'], stdout=DEVNULL)
          hcidump = ptyprocess.PtyProcess.spawn(['sudo', '-n', 'hcidump', '--raw'])
          return (hcitool, hcidump)